The use of light for healing has long been practiced. Specific light wavelengths have been used to treat various ailments and to stimulate the body's natural tissue healing abilities. Light emitting diodes (LEDs) that emit light in the red wavelength (around 630 nm-700 nm) have been shown to decrease pain, aid in wound healing, and increase skin rejuvenation.
The mechanism of how red light therapy aids in tissue healing is not completely understood, but red light has been shown to increase release of ATP, an important source of energy, which thereby aids in activity performance. (See “Light-emitting diode therapy in exercise-trained mice increases muscle performance, Cytochrome C oxidase activity, ATP and cell proliferation,” Ferraesi et al., J Biophotonics. 2016 September; 9(9):976). Light, especially light in the red and near-infrared range has been shown to have the ability to penetrate skin layers and energize fibroblast cells to produce collagen and elastin, which helps repair skin damage. LED light therapy has also been shown to increase growth of epithelial cells, improve recovery of musculoskeletal training injuries, and reduce pain in children suffering from oral mucositis. (See “Effect of NASA Light-Emitting Diode Irradiation on Wound Healing,” Whelan HT, J Clin Laser Med Surg. 2001 December; 19(6):305-314). Animal studies have shown that LED light therapy increases cell growth in mouse-derived fibroblasts, rat-derived osteoblasts, rat-derived skeletal muscle cells and also has the ability to decrease wound size. Id.
Most devices that use LEDs for healing, such as the device disclosed European Pat. App. Pub. No. EP2044973A1 to Vibor, are based on using a matrix of LEDs on a matrix board. These types of devices are similar to tanning beds, except instead of UV lamps within the bed, the lamps are replaced with red LEDs. Although the large bed devices are useful for treating certain types of tissue damage, they are bulky and expensive. They also require the user to dedicate several hours per week in order to receive a sufficient amount of light to observe positive effects.
In additional to LED beds, other types of devices have been used to aid in body repair. Light therapy bandages have been used to treat wounds, such as the one disclosed in U.S. Patent Pub. No. 20070233208A1 to Kurtz et al. Bandage devices such as these are most effective for topical wounds. Other devices, such U.S. Patent Pub. No. 20090088824A1 to Baird et al. uses a handheld wand-like device for LED based phototherapy to rejuvenate cells.
In addition to devices that stream a constant light source to a wounded area, therapy devices also exist that pulse light to treat wounds, such as the wand device disclosed in U.S. Patent Pub. No. 20050015121A1 to Molina, which uses pulsed light having a wavelength between 600 nm to about 980 nm, well into the infra-red range. While these devices may be effective to treat certain types of wounds in specific areas of the body, there remains a need for light therapy devices that are easy to use, inexpensive to manufacture and can effectively treat wounds that have traditionally been difficult to expose to light.